Town officials last week upheld a $30 ticket issued to a New Canaan woman who parked in a loading zone downtown. Sara Rehnberg told members of the Parking Commission during an appeal hearing Thursday that she thought the signs on the west side of South Avenue off of Elm Street were meant to prevent motorists from blocking the alley between an antiques store and the former Mackenzie’s space. “That was always my understanding,” she told the Commission during its regular meeting, held via videoconference. Rehnberg was ticketed at 12:16 p.m. on April 21 (a Wednesday) for parking in the loading zone. “I have parked there before, in the past.